RESUMO
The antibiofilm activity of a hypochlorous acid (HOCl)-producing electrochemical bandage (e-bandage) was assessed against 14 yeast isolates in vitro. The evaluated e-bandage was polarized at +1.5 VAg/AgCl to allow continuous production of HOCl. Time-dependent decreases in the biofilm CFU counts were observed for all isolates with e-bandage treatment. The results suggest that the described HOCl-producing e-bandage could serve as a potential alternative to traditional antifungal wound biofilm treatments.
Assuntos
Ácido Hipocloroso , Saccharomyces cerevisiae , Ácido Hipocloroso/farmacologia , Antifúngicos/farmacologia , Bandagens , BiofilmesRESUMO
The activity of a hypochlorous acid-producing electrochemical bandage (e-bandage) in preventing methicillin-resistant Staphylococcus aureus infection (MRSA) infection and removing biofilms formed by MRSA was assessed using a porcine explant biofilm model. e-Bandages inhibited S. aureus infection (p = 0.029) after 12 h (h) of exposure and reduced 3-day biofilm viable cell counts after 6, 12, and 24 h exposures (p = 0.029). Needle-type microelectrodes were used to assess HOCl concentrations in explant tissue as a result of e-bandage treatment; toxicity associated with e-bandage treatment was evaluated. HOCl concentrations in infected and uninfected explant tissue varied between 30 and 80 µM, decreasing with increasing distance from the e-bandage. Eukaryotic cell viability was reduced by an average of 71% and 65% in fresh and day 3-old explants, respectively, when compared to explants exposed to nonpolarized e-bandages. HOCl e-bandages are a promising technology that can be further developed as an antibiotic-free treatment for wound biofilm infections.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecção dos Ferimentos , Suínos , Animais , Ácido Hipocloroso/farmacologia , Staphylococcus aureus , Biofilmes , Bandagens , Infecção dos Ferimentos/prevenção & controle , Antibacterianos/farmacologiaRESUMO
AIMS: As antimicrobial resistance is on the rise, treating chronic wound infections is becoming more complex. The presence of biofilms in wound beds contributes to this challenge. Here, the activity of a novel hypochlorous acid (HOCl) producing electrochemical bandage (e-bandage) against monospecies and dual-species bacterial biofilms formed by bacteria commonly found in wound infections was assessed. METHODS AND RESULTS: The system was controlled by a wearable potentiostat powered by a 3V lithium-ion battery and maintaining a constant voltage of + 1.5V Ag/AgCl, allowing continuous generation of HOCl. A total of 19 monospecies and 10 dual-species bacterial biofilms grown on polycarbonate membranes placed on tryptic soy agar (TSA) plates were used as wound biofilm models, with HOCl producing e-bandages placed over the biofilms. Viable cell counts were quantified after e-bandages were continuously polarized for 2, 4, 6, and 12 hours. Time-dependent reductions in colony forming units (CFUs) were observed for all studied isolates. After 12 hours, average CFU reductions of 7.75 ± 1.37 and 7.74 ± 0.60 log10 CFU/cm2 were observed for monospecies and dual-species biofilms, respectively. CONCLUSIONS: HOCl producing e-bandages reduce viable cell counts of in vitro monospecies and dual-species bacterial biofilms in a time-dependent manner in vitro. After 12 hours, >99.999% reduction in cell viability was observed for both monospecies and dual-species biofilms.
Assuntos
Ácido Hipocloroso , Infecção dos Ferimentos , Humanos , Ácido Hipocloroso/farmacologia , Bactérias , Bandagens , BiofilmesRESUMO
Wound infections are caused by bacteria and/or fungi. The presence of fungal biofilms in wound beds presents a unique challenge, as fungal biofilms may be difficult to eradicate. The goal of this work was to assess the in vitro antibiofilm activity of an H2O2-producing electrochemical bandage (e-bandage) against 15 yeast isolates representing commonly encountered species. Time-dependent decreases in viable biofilm CFU counts of all isolates tested were observed, resulting in no visible colonies with 48 h of exposure by plate culture. Fluorescence microscopic analysis showed extensive cell membrane damage of biofilm cells after e-bandage treatment. Reductions in intracellular ATP levels of yeast biofilm cells were recorded post e-bandage treatment. These results suggest that exposure to H2O2-producing e-bandages reduces in vitro viable cell counts of yeast biofilms, making this a potential new topical treatment approach for fungal wound infections.
Assuntos
Bandagens , Biofilmes , Peróxido de Hidrogênio , Infecção dos Ferimentos , Eletroquímica , Humanos , Peróxido de Hidrogênio/farmacologia , Infecção dos Ferimentos/microbiologia , Infecção dos Ferimentos/prevenção & controle , Leveduras/patogenicidadeRESUMO
AIMS: Effects of H2 O2 producing electrochemical-bandages (e-bandages) on methicillin-resistant Staphylococcus aureus colonization and biofilm removal were assessed using a porcine explant biofilm model. Transport of H2 O2 produced from the e-bandage into explant tissue and associated potential toxicity were evaluated. METHODS AND RESULTS: Viable prokaryotic cells from infected explants were quantified after 48 h treatment with e-bandages in three ex vivo S. aureus infection models: (1) reducing colonization, (2) removing young biofilms and (3) removing mature biofilms. H2 O2 concentration-depth profiles in explants/biofilms were measured using microelectrodes. Reductions in eukaryotic cell viability of polarized and nonpolarized noninfected explants were compared. e-Bandages effectively reduced S. aureus colonization (p = 0.029) and reduced the viable prokaryotic cell concentrations of young biofilms (p = 0.029) with limited effects on mature biofilms (p > 0.1). H2 O2 penetrated biofilms and explants and reduced eukaryotic cell viability by 32-44% compared to nonpolarized explants. CONCLUSIONS: H2 O2 producing e-bandages were most active when used to reduce colonization and remove young biofilms rather than to remove mature biofilms. SIGNIFICANCE AND IMPACT OF STUDY: The described e-bandages reduced S. aureus colonization and young S. aureus biofilms in a porcine explant wound model, supporting their further development as an antibiotic-free alternative for managing biofilm infections.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Staphylococcus aureus , Suínos , Animais , Peróxido de Hidrogênio/farmacologia , Biofilmes , Bandagens , Antibacterianos/farmacologiaRESUMO
Hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) are biocides used for cleaning and debriding chronic wound infections, which often harbor drug resistant bacteria. Here, we evaluated the in vitro activity of H2O2 and HOCl against 27 isolates of eight bacterial species involved in wound infections. Minimum inhibitory concentrations (MICs) and minimum biofilm bactericidal concentrations (MBBCs) were measured. When compared to their respective MICs, MBBCs of isolates exposed to H2O2 were 16- to 1,024-fold higher and those exposed to HOCl were 2- to 4-fold higher. We evaluated selection of resistance after exposure of Staphylococcus aureus and Pseudomonas aeruginosa biofilms to 10 iterations of electrochemically generated HOCl or H2O2 delivered using electrochemical scaffolds (e-scaffolds), observing no decrease in anti-biofilm effects with serial exposure to e-scaffold-generated H2O2 or HOCl. 24-hour exposure to H2O2-generating e-scaffolds consistently decreased colony forming units (CFUs) of S. aureus and P. aeruginosa biofilms by â¼5.0-log10 and â¼4.78-log10 through 10 iterations of exposure, respectively. 4-hour exposure to HOCl-generating e-scaffolds consistently decreased CFUs of S. aureus biofilms by â¼4.9-log10, and 1-hour exposure to HOCl-generating e-scaffolds consistently decreased CFUs of P. aeruginosa biofilms by â¼1.57-log10 These results suggest that HOCl has similar activity against planktonic and biofilm bacteria, whereas the activity of H2O2 is less against biofilm than planktonic bacteria, and that repeat exposure to either biocide, generated electrochemically under the experimental conditions studied, does not lessen antibiofilm effects.
RESUMO
Oxidizing agents like hypochlorous acid (HOCl) have antimicrobial activity. We developed an integrated electrochemical scaffold, or e-scaffold, that delivers a continuous low dose of HOCl aimed at targeting microbial biofilms without exceeding concentrations toxic to humans as a prototype of a device being developed to treat wound infections in humans. In this work, we tested the device against 33 isolates of bacteria (including isolates with acquired antibiotic resistance) grown as in vitro biofilms alongside 12 combinations of dual-species in vitro biofilms. Biofilms were grown on the bottoms of 12-well plates for 24 h. An integrated e-scaffold was placed atop each biofilm and polarized at 1.5 V for 1, 2, or 4 h. HOCl was produced electrochemically by oxidizing chloride ions (Cl-) in solution to chlorine (Cl2); dissolved Cl2 spontaneously dissociates in water to produce HOCl. The cumulative concentration of HOCl produced at the working electrode in each well was estimated to be 7.89, 13.46, and 29.50 mM after 1, 2, and 4 h of polarization, respectively. Four hours of polarization caused an average reduction of 6.13 log10 CFU/cm2 (±1.99 log10 CFU/cm2) of viable cell counts of monospecies biofilms and 5.53 log10 CFU/cm2 (±2.31 log10 CFU/cm2) for the 12 dual-species biofilms studied. The described integrated e-scaffold reduces viable bacterial cell counts in biofilms formed by an array of antibiotic-susceptible and -resistant bacteria alone and in combination.
Assuntos
Ácido Hipocloroso , Infecção dos Ferimentos , Antibacterianos/farmacologia , Bactérias , Biofilmes , Humanos , Ácido Hipocloroso/farmacologiaRESUMO
Chronic wound infections caused by biofilm-forming microorganisms represent a major burden to healthcare systems. Treatment of chronic wound infections using conventional antibiotics is often ineffective due to the presence of bacteria with acquired antibiotic resistance and biofilm-associated antibiotic tolerance. We previously developed an electrochemical scaffold that generates hydrogen peroxide (H2 O2 ) at low concentrations in the vicinity of biofilms. The goal of this study was to transition our electrochemical scaffold into an H2 O2 -generating electrochemical bandage (e-bandage) that can be used in vivo. The developed e-bandage uses a xanthan gum-based hydrogel to maintain electrolytic conductivity between e-bandage electrodes and biofilms. The e-bandage is controlled using a lightweight, battery-powered wearable potentiostat suitable for use in animal experiments. We show that e-bandage treatment reduced colony-forming units of Acinetobacter buamannii biofilms (treatment vs. control) in 12 h (7.32 ± 1.70 vs. 9.73 ± 0.09 log10 [CFU/cm2 ]) and 24 h (4.10 ± 12.64 vs. 9.78 ± 0.08 log10 [CFU/cm2 ]) treatments, with 48 h treatment reducing viable cells below the limit of detection of quantitative and broth cultures. The developed H2 O2 -generating e-bandage was effective against in vitro A. baumannii biofilms and should be further evaluated and developed as a potential alternative to topical antibiotic treatment of wound infections.
Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii/crescimento & desenvolvimento , Bandagens , Biofilmes/crescimento & desenvolvimento , Técnicas Eletroquímicas , Peróxido de Hidrogênio , Infecção dos Ferimentos , Infecções por Acinetobacter/microbiologia , Infecções por Acinetobacter/terapia , Animais , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/farmacologia , Infecção dos Ferimentos/microbiologia , Infecção dos Ferimentos/terapiaRESUMO
The antibiofilm activity of a hydrogen peroxide-generating electrochemical scaffold (e-scaffold) was determined against mono- and trispecies biofilms of methicillin-resistant Staphylococcus aureus, multidrug-resistant Pseudomonas aeruginosa, and Candida albicans Significant time-dependent decreases were found in the overall CFU of biofilms of all three monospecies and the trispecies forms. Confocal laser scanning microscopy showed dramatic reductions in fluorescence intensities of biofilm matrix protein and polysaccharide components of e-scaffold-treated biofilms. The described e-scaffold has potential as a novel antibiotic-free strategy for treating wound biofilms.
Assuntos
Anti-Infecciosos/farmacologia , Biofilmes , Técnicas Eletroquímicas/métodos , Peróxido de Hidrogênio/metabolismo , Anti-Infecciosos/química , Biofilmes/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Contagem de Colônia Microbiana , Sistemas de Liberação de Medicamentos/métodos , Técnicas Eletroquímicas/instrumentação , Proteínas da Matriz Extracelular/metabolismo , Peróxido de Hidrogênio/química , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Microscopia Confocal , Polissacarídeos/metabolismo , Pseudomonas aeruginosa/efeitos dos fármacos , Fatores de TempoRESUMO
We previously demonstrated that shotgun metagenomic sequencing can detect bacteria in sonicate fluid, providing a diagnosis of prosthetic joint infection (PJI). A limitation of the approach that we used is that data analysis was time-consuming and specialized bioinformatics expertise was required, both of which are barriers to routine clinical use. Fortunately, automated commercial analytic platforms that can interpret shotgun metagenomic data are emerging. In this study, we evaluated the CosmosID bioinformatics platform using shotgun metagenomic sequencing data derived from 408 sonicate fluid samples from our prior study with the goal of evaluating the platform vis-à-vis bacterial detection and antibiotic resistance gene detection for predicting staphylococcal antibacterial susceptibility. Samples were divided into a derivation set and a validation set, each consisting of 204 samples; results from the derivation set were used to establish cutoffs, which were then tested in the validation set for identifying pathogens and predicting staphylococcal antibacterial resistance. Metagenomic analysis detected bacteria in 94.8% (109/115) of sonicate fluid culture-positive PJIs and 37.8% (37/98) of sonicate fluid culture-negative PJIs. Metagenomic analysis showed sensitivities ranging from 65.7 to 85.0% for predicting staphylococcal antibacterial resistance. In conclusion, the CosmosID platform has the potential to provide fast, reliable bacterial detection and identification from metagenomic shotgun sequencing data derived from sonicate fluid for the diagnosis of PJI. Strategies for metagenomic detection of antibiotic resistance genes for predicting staphylococcal antibacterial resistance need further development.
Assuntos
Bactérias/isolamento & purificação , Biologia Computacional/métodos , Análise de Dados , Prótese Articular/microbiologia , Metagenômica/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Farmacorresistência Bacteriana , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Infecções Relacionadas à Prótese/diagnóstico , Sensibilidade e Especificidade , Sonicação/métodos , Manejo de Espécimes/métodos , Adulto JovemRESUMO
A biomedical sensor was developed to measure local pH near orthopedic implants to detect and study implant-associated infection. The sensor is read using plain radiography, a technique which is noninvasive, inexpensive, ubiquitously available in medical facilities, and routinely used in diagnosis and follow-up. The sensor comprises a radiopaque tungsten indicator pin embedded within a chemically responsive hydrogel that exhibits a pH-dependent swelling. A stainless steel well holds this hydrogel and attaches to an orthopedic plate. The local pH may be determined from the extent of hydrogel swelling by radiographically measuring the indicator position relative to the well. We calibrated the sensor in a series of standard pH buffers and tested it during bacterial growth in culture. The sensor was robust: its response was negligibly affected by changes in temperature, ionic strength within the normal physiological range, or long-term incubation with reactive oxygen species generated from hydrogen peroxide and copper. Pooled data from several sensors fabricated at different times and tested in different conditions had a root-mean-square deviation from a pH electrode reading of 0.24 pH units. Radiographic measurements were also performed in cadaveric tissue with the sensor attached to an orthopedic plate fixed to a tibia. Pin position readings varied by 100 µm between observers surveying the same radiographs, corresponding to 0.065 pH units precision in the range pH 4-8. The sensor was designed to augment standard radiographs of tissue, bony anatomy, and hardware by also indicating local chemical concentrations.
Assuntos
Resinas Acrílicas/química , Hidrogéis/química , Próteses e Implantes/microbiologia , Radiografia/métodos , Humanos , Concentração de Íons de Hidrogênio , Staphylococcus aureus/metabolismoRESUMO
The antibiofilm activity of oritavancin in combination with rifampin, gentamicin, or linezolid was evaluated against 10 prosthetic joint infection (PJI)-related methicillin-resistant Staphylococcus aureus (MRSA) isolates by time-kill assays. Oritavancin combined with rifampin demonstrated statistically significant bacterial reductions compared with those of either antimicrobial alone for all 10 isolates (P ≤ 0.001), with synergy being observed for 80% of the isolates. Oritavancin and rifampin combination therapy may be an option for treating MRSA PJI.
Assuntos
Biofilmes/efeitos dos fármacos , Gentamicinas/farmacologia , Linezolida/farmacologia , Lipoglicopeptídeos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Rifampina/farmacologia , Testes de Sensibilidade MicrobianaRESUMO
The separation of particles and cells in a uniform mixture has been extensively studied as a necessity in many chemical and biomedical engineering and research fields. This work demonstrates a continuous charge-based separation of fluorescent and plain spherical polystyrene particles with comparable sizes in a ψ-shaped microchannel via the wall-induced electrical lift. The effects of both the direct current electric field in the main-branch and the electric field ratio in between the inlet branches for sheath fluid and particle mixture are investigated on this electrokinetic particle separation. A Lagrangian tracking method based theoretical model is also developed to understand the particle transport in the microchannel and simulate the parametric effects on particle separation. Moreover, the demonstrated charge-based separation is applied to a mixture of yeast cells and polystyrene particles with similar sizes. Good separation efficiency and purity are achieved for both the cells and the particles.
Assuntos
Separação Celular/métodos , Técnicas Analíticas Microfluídicas/métodos , Simulação por Computador , Eletricidade , Modelos Teóricos , Tamanho da Partícula , Poliestirenos/química , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/isolamento & purificaçãoRESUMO
Preconcentrating samples of dilute particles or cells to a detectable level is required in many chemical, environmental and biomedical applications. A variety of force fields have thus far been demonstrated to capture and accumulate particles and cells in microfluidic devices, which, however, all take place within the region of microchannels and may potentially cause channel clogging. This work presents a new method for the electrokinetic preconcentration of 1 µm-diameter polystyrene particles and E. coli cells in a very-low-conductivity medium inside a microfluidic reservoir. The entire microchannel can hence be saved for a post-concentration analysis. This method exploits the strong recirculating flows of induced-charge electroosmosis to concentrate particles and cells near the corners of the reservoir-microchannel interface. Positive dielectrophoresis is found to also play a role when small microchannels are used at high electric fields. Such an in-reservoir electrokinetic preconcentration method can be easily implemented in a parallel mode to increase the flow throughput, which may potentially be used to preconcentrate bacterial pathogens in water.
Assuntos
Métodos Analíticos de Preparação de Amostras/instrumentação , Dispositivos Lab-On-A-Chip , Condutividade Elétrica , Escherichia coli/citologia , Poliestirenos/químicaRESUMO
Chronic wound biofilm infections represent a major clinical challenge which results in a substantial burden to patients and healthcare systems. Treatment with topical antibiotics is oftentimes ineffective as a result of antibiotic-resistant microorganisms and biofilm-specific antibiotic tolerance. Use of biocides such as hypochlorous acid (HOCl) has gained increasing attention due to the lack of known resistance mechanisms. We designed an HOCl-generating electrochemical bandage (e-bandage) that delivers HOCl continuously at low concentrations targeting infected wound beds in a similar manner to adhesive antimicrobial wound dressings. We developed a battery-operated wearable potentiostat that controls the e-bandage electrodes at potentials suitable for HOCl generation. We demonstrated that e-bandage treatment was tunable by changing the applied potential. HOCl generation on electrode surfaces was verified using microelectrodes. The developed e-bandage showed time-dependent responses against in vitro Acinetobacter baumannii and Staphylococcus aureus biofilms, reducing viable cells to non-detectable levels within 6 and 12 hours of treatment, respectively. The developed e-bandage should be further evaluated as an alternative to topical antibiotics to treat wound biofilm infections.
RESUMO
Biofilms formed by antibiotic-resistant bacteria in wound beds present unique challenges in terms of treating wound infections. In this work, the in vivo activity of a novel electrochemical bandage (e-bandage) composed of carbon fabric and controlled by a wearable potentiostat, designed to continuously deliver low amounts of hydrogen peroxide (H2O2) was evaluated against methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa (MDR-PA) and mixed-species (MRSA and MDR-PA) wound infections. Wounds created on Swiss Webster mice were infected with the above-named bacteria and biofilms allowed to establish on wound beds for 3 days. e-Bandages, which electrochemically reduce dissolved oxygen to H2O2 when polarized at -0.6 VAg/AgCl, were placed atop the infected wound bed and polarized continuously for 48 hours. Polarized e-bandage treatment resulted in significant reductions (p <0.001) of both mono-species and mixed-species wound infections. After e-bandage treatment, electron microscopy showed degradation of bacterial cells, and histopathology showed no obvious alteration to the inflammatory host response. Blood biochemistries showed no abnormalities. Taken all together, results of this work suggest that the described H2O2-producing e-bandage can effectively reduce in vivo MRSA, MDR-PA and mixed-species wound biofilms, and should be further developed as a potential antibiotic-free strategy for treatment of wound infections.
RESUMO
The ability of ten polyphenolic antioxidants to prevent CuO nanoparticle (NPCuO) and H2O2-mediated DNA damage and cytotoxicity was investigated. Five of the polyphenols (MEPCA, PREGA, MEGA, ECG, and EGCG) prevent NPCuO/H2O2-mediated DNA damage (IC50 values of 7.5-800 µM), three have no effect (PCA, VA, and EC), and two (GA and EGC) result in increased DNA damage. Most polyphenols had similar antioxidant/prooxidant activity in the presence of NPCuO or free copper ions. Electron paramagnetic resonance (EPR) spectroscopy of reactive oxygen species (ROS) generated by NPCuO/H2O2 in the presence of representative polyphenols correlate with results of DNA damage studies: in the presence of NPCuO/H2O2, MEPCA prevents ROS formation, VA has no effect on ROS levels, and EGC increases ROS levels. EPR results with CuO nanoparticles washed to remove dissolved copper in solution (wCuO) in the presence of H2O2/ascorbate suggest that MEPCA prevents ROS formation on the nanoparticle surface in addition to preventing ROS formation from dissolved copper. In mouse fibroblast (L929) cells, combining NPCuO with H2O2 results in significantly greater cytotoxicity than observed for either component alone. After 3 h incubation with MEPCA or MEGA, the viability loss in L929 cells induced by NPCuO/H2O2 challenge was significantly rescued at physiologically relevant polyphenol levels (1 µM). These studies show that polyphenols can protect DNA and inhibit cytotoxicity generated by NPCuO under oxidative stress conditions.
Assuntos
Cobre/toxicidade , Nanopartículas Metálicas/toxicidade , Polifenóis/farmacologia , Animais , Morte Celular/efeitos dos fármacos , Linhagem Celular , Dano ao DNA/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Peróxido de Hidrogênio/toxicidade , Camundongos , Espécies Reativas de Oxigênio/metabolismoRESUMO
Previously, an electrochemical bandage (e-bandage) that uses a three-electrode system to produce hydrogen peroxide (H2O2) electrochemically on its working electrode was developed as a potential strategy for treating biofilms; it showed activity in reducing biofilms in an agar biofilm model. Xanthan gum-based hydrogel, including NaCl, was used as the electrolyte. While H2O2 generated at the working electrode in the vicinity of a biofilm is a main mechanism of activity, the role of the counter electrode was not explored. The goal of this research was to characterize electrochemical reactions occurring on the counter electrode of the e-bandage. Counter electrode potential varied between 1.2 and 1.5 VAg/AgCl; â¼125 µM hypochlorous acid (HOCl) was generated within 24 h in the e-bandage system. When HOCl was not produced on the counter electrode (achieved by removing NaCl from the hydrogel), reduction of Acinetobacter baumannii BAA-1605 biofilm was 1.08 ± 0.38 log10 CFU/cm2 after 24 h treatment, whereas when HOCl was produced, reduction was 3.87 ± 1.44 log10 CFU/cm2. HOCl inhibited catalase activity, abrogating H2O2 decomposition. In addition to H2O2 generation, the previously described H2O2-generating e-bandage generates HOCl on the counter electrode, enhancing its biocidal activity.
Assuntos
Peróxido de Hidrogênio , Ácido Hipocloroso , Ágar , Bandagens , Catalase , Hidrogéis/farmacologia , Peróxido de Hidrogênio/farmacologia , Ácido Hipocloroso/farmacologia , Cloreto de SódioRESUMO
We have previously demonstrated that iron oxide nanoparticles with dopamine-anchored heterobifunctional polyethylene oxide (PEO) polymer, namely PEO-IONPs, and bio-functionalized with sialic-acid specific glycoconjugate moiety (Neu5Ac(α2-3)Gal(ß1-4)-Glcß-sp), namely GM3-IONPs, can be effectively used as antibacterial agents against target Escherichia coli. In this study, we evaluated the biocompatibility of PEO-IONPs and GM3-IONPs in a normal human colon cell line CCD-18Co via measuring cell proliferation, membrane integrity, and intracellular adenosine triphosphate (ATP), glutathione GSH, dihydrorhodamine (DHR) 123, and caspase 3/7 levels. PEO-IONPs caused a significant decrease in cell viability at concentrations above 100 µg/mL whereas GM3-IONPs did not cause a significant decrease in cell viability even at the highest dose of 500 µg/mL. The ATP synthase activity of CCD-18Co was significantly diminished in the presence of PEO-IONPs but not GM3-IONPs. PEO-IONPs also compromised the membrane integrity of CCD-18Co. In contrast, cells exposed to GM3-IONPs showed significantly different cell morphology, but with no apparent membrane damage. The interaction of PEO-IONPs or GM3-IONPs with CCD-18Co resulted in a substantial decrease in the intracellular GSH levels in a time- and concentration-dependent manner. Conversely, levels of DHR-123 increased with IONP concentrations. Levels of caspase 3/7 proteins were found to be significantly elevated in cells exposed to PEO-IONPs. Based on the results, we assume GM3-IONPs to be biocompatible with CCD-18Co and could be further evaluated for selective killing of pathogens in vivo.
RESUMO
Biofilms formed by antibiotic-resistant bacteria in wound beds present unique challenges in terms of treating chronic wound infections; biofilms formed by one or more than one bacterial species are often involved. In this work, the in vitro anti-biofilm activity of a novel electrochemical bandage (e-bandage) composed of carbon fabric and controlled by a wearable potentiostat, designed to continuously deliver low amounts of hydrogen peroxide (H2O2) was evaluated against 34 mono-species and 12 dual-species membrane bacterial biofilms formed by Staphylococcus aureus, S. epidermidis, Enterococcus faecium, E. faecalis, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Cutibacterium acnes, and Bacteroides fragilis. Biofilms were grown on polycarbonate membranes placed atop agar plates. An e-bandage, which electrochemically reduces dissolved oxygen to H2O2 when polarized at -0.6 VAg/AgCl, was then placed atop each membrane biofilm and polarized continuously for 12, 24, and 48 h using a wearable potentiostat. Time-dependent decreases in viable CFU counts of all mono- and dual-species biofilms were observed after e-bandage treatment. 48 h of e-bandage treatment resulted in an average reduction of 8.17 ± 0.40 and 7.99 ± 0.32 log10 CFU/cm2 for mono- and dual-species biofilms, respectively. Results suggest that the described H2O2 producing e-bandage can reduce in vitro viable cell counts of biofilms grown either in mono- or dual-species forms, and should be further developed as a potential antibiotic-free treatment strategy for treating chronic wound infections.